Re: [MLUG] perl question

[Mike Miller <EMAIL:PROTECTED>]

On Tue, 2 May 2006, Rick wrote:

> Would this work?
>
> cat file | egrep "^1" | sed 's/x //'

That's the sort of thing I'm trying to avoid (see comments about egrep 
below).  But that also isn't right -- it removes every line that does not 
begin with 1.  This is more like it:

egrep "^1" file | sed 's/x/ /' > part1
egrep -v "^1" file > part2
cat part1 part2 | sort > outfile

This works because my file is sorted, but if the file was not sorted and 
the order mattered, this also would fail (that's why I was talking about 
"cat -n" below - I could add line numbers for sorting purposes).

Mike


> Mike Miller wrote:
> > This must be something I can do in a one-liner:  Suppose I have a file 
> > where I want to remove all occurances of a certain character from lines 
> > that match a pattern, like all 'x' characters from every line that begins 
> > with '1':
> >
> > 3 7 x 5 x 9
> > 1 x 2 2 z x
> > 9 9 9 x 9 9
> > 1 2 23 x 7
> >
> > Maybe I want to replace every 'x' with a space only when the first 
> > character in the line is a '1', otherwise I leave the x's alone.  Any 
> > ideas?
> >
> > The way I would do it is lame:  Remove the lines beginning with 1, process 
> > them, then put them back.  I would do egrep twice (once with -v), maybe 
> > using cat -n to add line numbers, then take out the x's and put them back 
> > together, sort, take out the line numbers.  That is embarrassing though.
> >
> > Mike
>
> --
> We simply can't idiot-proof everything. Sometimes the idiots just have to 
> suffer and die.
> --http://www.overheardintheoffice.com/
>
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